The experiments in this proposal are designed to determine the geometry of the orderly arrangement of direction selective neurons in cat visual cortical areas 17 and 18. These experiments will use single unit recording techniques with computer controlled stimulus presentation and data collection. Preliminary data indicate a highly ordered system of direction subunits in both areas 17 and 18, with supra- and infragranular layers having opposite direction preferences within each orientation column. These preliminary data will be confirmed and differences in this organization between striate cortex (area 17) and an extrastriate area (area 18) will be assessed. The long term objectives of this proposal are to increase our understanding of how the cortex processes information about visual motion and to extend these studies to other cortical and subcortical areas to determine how motion is represented in the brain.